Non-woven fabric prepared with methylol amides of an adduct formed between a maleyl compound and an ethylenically unsaturated aliphatic compound



United States Patent 3,345,207 NON-WOVEN FABRIC PREPARED WITH METH- YLOLAMIDES OF AN ADDUCT FORMED BE- TWEEN A MALEYL COMPOUND AND ANETHYLENICALLY UNSATURATED ALIPHAT- IC COMPOUND George W. Cogswell andLester P. Hayes, Decatur, 11L, assignors to A. E. Staley ManufacturingCompany, Decatur, Ill, a corporation of Delaware No Drawing. Filed June20, 1963, Ser. No. 289,384 18 Claims. (Cl. 117-140) This inventionrelates to bonded non-Woven fibrous or filamentous productshaving acarded fiber structure or comprising fibrous mats in which the fiber orfilaments are distributed haphazardly or in random array. The inventionalso relates to methods for producing the bonded non-woven fibrousproducts or shaped articles therefrom.- The bonded non-Woven fibrousproducts are useful in the production of articles of either fiat orthree-dimensional shape, including insulating material and the like aswill be described more particularly hereinafter.

Hereinafter, the expression random array is intended to include thearray of fibers in a carded Web wherein partial orientation isfrequently present as Well as other arrays in which the fibers are in acompletely haphazard distributional relationship.

Heretof-ore, binders of natural rubber latex and aqueous dispersions ofsynthetic rubbers, such as butadiene copolymerized with styrene,acrylonitrile and so on have been suggested as binders for bonding thefibers is nonwoven fabric structures; but these'materials have variousdisadvantages. These rubbery binders produce a rubbery hand whichappears to be the result of a complete suppression of the fibrouscharacter insofar as the feel of the product is concerned. When bindersof polyvinyl acetates, chlorides, or their copolymers are used, the handbecomes papery, by which is meant that the product has a noisy, crisp,brittle hand and eonveys the impression of thinness and fragility.Further, the water-resistance and solvent resistance of some of theseproducts leaves something to be desired. The application ofthermoplastic polymers of monomers such as simple esters of acrylic ormethacrylic acid produces products in which the binder remainspermanently thermoplastic with consequent tendency to change whensubjected to excessive temperatures. The simple polymers of acrylic andmethacrylicacid esters are also characterized by relatively pooradhesion to hydrophobic types of fibers, such as nylon, vinyl resinfibers, cellulose esters, and polyesters such as polyethylene glycolterephthalate. Furthermore, many of the binders heretofore employed,including the aqueous dispersion of rubber, synthetic rubbers andacrylic ester polymers, have a strong tendency to migrate to the surfaceof the fibrous products during drying of the products to which thedispersion have been applied. In addition to the foregoing, many ofthese binders, particularly aqueous dispersions of the polyacrylicesters, are relatively expensive.

The object of this invention is to provide fibrous products made with aninexpensive binder which can be applied by way of an aqueous systemWithin the disadvantages mentioned above that are characteristic ofpreviously applied aqueous binder systems. Another object of thisinvention is to provide a bonded fibrous product of non- Woven characterin which the binder is adapted to be converted to an infusible andinsoluble condition as by heating with or Without the presence of asuitable catalyst as will be pointed out more particularly hereinafter.A further object of this invention is to provide bonded fibrous productsof non-woven character wherein the binder may be substantially uniformlydistributed through the body of the structure and has reduced tendencyto migrate to the surfaces of the structure.

Patented Oct. 3, 1%?

A still further object of this invention is to provide a low costauxiliary binder for use with conventional non- Woven binders, whichincreases the Water and solvent resistance of binders such as polyvinylacetate, which increases the adhesion of binders such as the simpleacrylate polymers, which prevents the flow of thermoplastic binders,etc.

According to the present invention, it has been found that aqueousdispersions of the reaction product of formaldehyde With amide adductsof alpha, beta-ethylenically unsaturated dicarboxy compounds (maleylcompounds) and ethylenically unsaturated compound having a chain of atleast 10 carbon atoms are capable of bonding fibers of a non-wovenfibrous product. As explained in detail in commonly assigned applicationSer. No. 264,069,,filed Mar. 11, 1963, these methylol amide adducts canbe prepared by (1) forming an adduct of an alpha,beta-ethylenicallyunsaturated dicarboxy compound (maleyl compound) and a longe chainethylenically unsaturated compound having a chain of from 10-24 carbonatoms,- (2) reacting said adduct with a basic nitrogen compound, whichcontains at least two active hydrogen atoms bonded to the same ordifferent nitrogen atoms in the same molecule, and (3) reacting theproduct of step (2) with a formaldehyde source.

In the description that follows, the words dispersing and dispersion areused in a generic sense to be inclusive of the words suspending,dissolving, suspension, and solution. The words ammonia and ammoniumhydroxide are used interchangeably. The term formaldehyde is used in ageneric sense to be inclusive of monomeric formaldehyde andformaldehyde-generating materials. The term potentially reactive carboxygroup includes the following reactive groups: the amide group, themethylol. amide group, the anhydride group, the free carboxylic acidgroup and carboxylic acid salt groups.

The long chain ethylenically unsaturated compounds can be substituted orcontain various other groups such as carboxyl groups, carboxylategroups, halo groups, acyloxy groups, alkoxy groups, aryloxy groups,tertiary amino groups, quaternary ammonium groups, etc. The preferredlong-chain ethylenically unsaturated compounds of this invention are thereadily available, naturally occurring polyunsaturated glyceride oils(which are considered as having carboxylate groups) having from 10 to 24carbon atoms in the unsaturated long chain, such as soybean oil, cornoil, cottonseed oil, hempseed oil, tung oil, safflower oil, peanut oil,linseed oil, tobacco seed oil, cod oil, herring (or menhaden) oil,dehydrated castor oil, etc. The glyceride oils and the esters of otherunsaturated long chain acids, such as the linoleic acid esters oftrimethylol propane and tall oil fatty acid esters of pentaerythritol,are preferred since they contain a relatively large number of ethylenicdouble bonds available as sites for adduct formation. In general, thosecompounds having on an average at least two and preferably three to ninenonconjugated ethylenically unsaturated groups per molecule arepreferred. These can be thought of as being esters of a polyhydricalcohol (e.g. ethylene glycol, trimethylol ethane, sorbitol, inositol,etc.) having from 2 to 6 hydroxyl groups with ethylenically unsaturatedfatty acid chains of from 10 to 25 carbon atoms.

. Other useful long chain fatty compounds include methyl oleate, 2-ethylhexyl ester of tall oil fatty acids, oleic acid, linoleic acid,linolenic acid, ammonium linoleate, N-unsubstituted linoleamide,octadecene-9, l-chlorodecene-4, 1-bromooctadecene-9,1-chlorotetracosene-9, 1- nitrilooctadecene-9; N,N-dimethyllinoleamide,N,N-linoleimide, N,N-linolenimide, N,N-dimethyl-N,N-dilinoleyl amine,N-methyl-N,N-dilinoleylamine, IO-carboxydecene- 2,1-acetoxyoctadecene-4, 1-phenoxyoctadecene-9, l-propoxyoctadecene-9,etc.

The maleyl compound (alpha, beta-ethylenically unsaturated dicarboxycompound) can be maleic anhydride, maleic acid, fumaric acid, dimethylmaleate, monomethyl hydrogen maleate, mono-Z-ethylhexyl hydrogenmaleate, citraconic acid citraconic anhydride, itaconic acid itaconicanhydride, ethyl maleic acid, maleimide, maleamic acid, etc. Of these,maleic anhydride is preferred because of (1) its low cost, (2) the easewith which it forms adducts in almost quantitative yields, and (3) thehigh concentration of amide groups which result from the reaction of theanhydride adduct with a basic nitrogen compound. While maleic acid,which forms the anhydride, under the conditions of adduct formation hasmost of the advantages of maleic anhydride, it is twice as expensive asthe anhydride. Fumaric acid, which approaches the cost of maleicanhydride on a weight basis, requires considerably more severe reactionconditions to form an adduct and, even then, the yield is lower.Further, adducts prepared from free dicarboxylic acids that are notcapable of forming an anhydride under the conditions of the maleationreaction and from half-esters and diesters produce amides with a lowerconcentration of amide groups after treatment with a suitable basicnitrogen compound than corresponding adducts containing the sameconcentration of carboxy groups in the anhydride form. It goes withoutsaying that diesters are only suitable in this invention when at leastsome of the carboxy groups in the diester adduct are saponified duringor before the addition of the basic nitrogen compound to permit amideformation. Citric acid and malic acid which form alpha,-beta-ethylenically unsaturated dicarboxy compounds under the conditionsof the maleation reaction can also be used in this invention.

Ammonia, which can be employed as gaseous ammonia or in the aqueousammonium hydroxide form, is the preferred basic nitrogen compoundbecause of its low cost, availability, high vapor pressure in water, theease with which it forms amides and the ease with which its amides formmethylol groups. Various primary amines; such as methyl amine, ethylamine, and butyl amine; primary and secondary polyamines; such asethylene diamine, diethylene triamine, ropylene diamine andN,N'-dimethyl-ethylene diamine; can be used to partially or completelyre place ammonia. All of these amines contain at least two activehydrogen atoms which may be bonded to the same or to different nitrogenatoms in the same molecule.

Formaldehyde, generally as formalin, is the preferred source offormaldehyde. Polymeric forms of formaldehyde, such as trioxane andparaformaldehyde, are decidedly inferior to formaldehyde. Thesepolymeric groups must be employed at much higher temperatures than themonomeric formaldehyde. Of course, the polymeric form is equivalent tothe monomeric form if it is first converted to the monomeric form beforeaddition to the amide adducts. Reaction products of formaldehyde withbasic nitrogen compounds of the preceding paragraph (e.g.hexamethylenetetramine) are decidedly poorer than the individualreactants. Even in those cases where ammonia has been employed to formthe amide prior to the addition of hexamethylenetetramine, highertemperature must be employed to form the desired methylol amide thanwhen monomeric formaldehyde is used. Further, the detergent resistanceof non-woven fabrics prepared with formaldehyde condensation productsare inferior to the detergent resistance of non-woven fabrics preparedfrom monomeric formaldehyde.

In somewhat greater detail the adduct is formed by reacting the longchain ethylenically unsaturated fatty compound and the maleyl compoundat a temperature of about C. to 300 C. in an open vessel or underpressure in an autoclave. While maleic anhydride forms an adduct inalmost quantitative yields in an open vessel, other maleyl compounds,such as dibutyl maleate, give considerably better yields when thereaction is carried out under pressure.

The ratio of maleyl compound to ethylenically unsaturated long chainfatty compound in the reaction vessel can range from about 0.1 to 2moles or more of maleyl compound per equivalent of unsaturation in thelong chain fatty compound, depending upon the choice of reactants andthe desired properties of the products. For example, the preferrednaturally occurring glyceride oils, such as soybean oil or linseed oil,can be reacted with from about 10% to 45% by weight of maleic anhydrideto form adducts containing from about 1.0 to 4.5 maleic anhydridemoieties per molecule of glyceride oil. (The resulting maleic anhydrideportion of the glyceride oil adduct comprises from about 10% to 3% byweight of the product.) The properties of the various members vary, asfollows, depending upon the level of maleation.

Maleated glyceride oils, which contain about 10% by weight maleicanhydride or about 1.0 mole of anhydride per mole of glyceride oil, formstable suspensions in aqueous ammonium hydroxide while those containingin excess of about 14% by weight maleic anhydride or about 1.5 moles ofanhydride per mole of glyceride oil are soluble in aqueous ammoniumhydroxide. Methylol amides at the same level of maleation haveessentially the same dispersibility characteristics in aqueous base asthe anhydride adduct from which the methylol amide is formed. Otherthings being equal, non-woven fabrics prepared with glyceride oilmethylol amides vary as the level of maleation increases as follows:

in general, the methylol amides based upon unsaturated long chaincarboxylic acid esters of polyhydric alcohols containing a total of fromabout 2 to 4 potentially reactive carboxy groups (carboxylate salts,amide and methylol amide groups) per molecule (preferably about 3.5 to4) are suited particularly for use as non-woven binders for disposablewiping cloths (industrial dustcatching cloths). These cloths are notlaundered because of their low cost, poor detergent resistance and softabsorbent character. For the most part, laundering costs more than thecloth-s themselves.

The methylol amides based upon unsaturated fatty acid esters ofpolyhydric alcohols containing a total of about 4 to 9 potentiallyreactive carboxy groups per molecule (preferably about to 7) are suitedfor use as the vehicle for non-woven binders having excellentsolvent-resistance and detergent resistance and these are the preferredproducts of this invention.

The maleated long chain fatty material can be converted to the amide bya variety of techniques. For example, an anhydride adduct, such as thatresulting from the maleation of a naturally occurring glyceride oil andmaleic anhydride or maleic acid, can be converted to the amide form inany of the following ways: (1) stirring the anhydride adduct in anatmosphere of ammonia until the exothermic reaction ceases, (2) addingconcentrated ammonium hydroxide (28% aqueous solution, for example), tothe anhydride adduct and stirring until the adduct disperses, (3) addingthe anhydride adduct to concentrated ammonium hydroxide and stirringuntil the adduct disperses, (4) mixing the anhydride adduct with acalculated amount of water and then bubbling a sufficient amount ofammonia gas into the system to disperse the anhydride adduct, (5) mixingthe anhydride adduct with a calculated amount of'water, opening theanhydride ring by heating and then adding ammonia gas or aqueousammonium hydroxide to disperse the adduct.

It has been found that adding the anhydride adduct to concentratedammonium hydroxide yields the highest concentration of amide groups. Forexample, when the above illustrative anhydride adduct (glyceride oil andmaleic anhydride) is added to a concentrated aqueous ammonium hydroxidesolution containing two molecules of ammonium hydroxide per anhydridegroup in the adduct, about 85% of the anhydride groups (42.5% of thecarboxy groups) are converted to monoamide groups. The remainder of theammonium hydroxide is present as the ammonium salt. On the other hand,when the ammonium hydroxide is added to the adduct in the sameproportion, about 60% of the anhydride groups (30% of the potentiallyreactive carboxy groups) are converted to monoamide groups. About 30% ofthe anhydride groups are converted to monoamide groups when concentratedammonium hydroxide is added to the anhydride adduct in a ratio of onemolecule of ammonium hydroxide per anhydride group.

Still lower yields of amide are obtained if the anhydride ring is openedprior to the addition of ammonium hydroxide. For example, when theanhydride ring of the same adduct is first broken by heating with water,the addition of ammonium hydroxide to the adduct (in a ratio of onemolecule of ammonium hydroxide per anhydride ring produces only 15% ofamide-containing anhydride groups (7.5% of the carboxy groups).

While the combined number of potentially reactive carboxy groups permolecule of fatty material has a pronounced effect on the properties ofthe final non-woven fabric, the ratio of amide groups to carboxylatesalt groups has a smaller effect. For example, non-woven fabric basedupon glyceride oil adducts having on an average 0.9 amide group and 5.1carboxylate salt groups per molecule have properties quite similar tonon-woven fabrics based upon glyceride oil adducts having on an averagefrom about 1.8 to "about 2.6 amide groups and correspondingly 4.2 to 3.4carboxylate salt groups (6 5 potentially reactive carboxy groups permolecule). Other things being equal, the latter products have somewhatbetter detergent resistance, solvent resistance, and higher tensilestrength. Accordingly, products having higher ratios of amide groups tocarboxylate salt groups are preferred.

The amide adduct, which has preferably been dispersed in water, is thenreacted with formaldehyde or a compound capable of generatingformaldehyde preferably by adding the formaldehyde source (usuallyformalin or paraformaldehyde depolymerized to the monomeric form) to theamide adduct or by adding the amide adduct to the formaldehyde source.This reaction can be carried out in a sealed vessel at moderatetemperature (5 C. to 75 C.) or in an open vessel. A sufiicientconcentration of formaldehyde is added in this step to provide at least0.7 mole of formaldehyde per each equivalent of nitrogen containingcompound bearing a nitrogen atom bonded directly to hydrogen (each NHgroup) in the aqueous composition. V

Excellent results have been obtained by adding at least about 0.8 moleof formaldehyde for each mole of basic nitrogen containing compound,which contains two hydrogen atoms bonded directly to nitrogen, used toform the amide. In this Way essentially all the ammonium ions, etc. inthe reaction medium are converted to non-volatile nitrogen and themethylol amide adduct is precipitated from the aqueous reaction mediumas a water-insoluble hydrate. This frequently has a dough-likeconsistency. The formation of this precipitate is visual evidence that asufficient concentration of formaldehyde has been added to the amideadduct.

If less than 0.7 mole of formaldehyde per each equivalent ofnitrogen-containing compound is added to the aqueous amide adduct, themethylol amide-bound non- Woven fabric does not have water resistanceand detergent resistance. In fact, the water resistance and detergentresistance is in some cases only slightly better than that if thenon-woven fabric had been prepared with an amide adduct, which had notbeen reacted with formaldehyde.

After the formaldehyde reaction, the resultant methylol amide adduct isneutralized or made basic by the addition of a suitable basic material,preferably ammonium hydroxide or a volatile amine. Any precipitatedmethylol amide is thereby redispersed.

Non-volatile alkali is not preferred since non-woven fabrics basedthereon have poorer water resistance and detergent resistance. Diamines,such as ethylene diamine, are advantageously employed with ammonia in,order to give the cured products a somewhat softer, more flexiblecharacter. Ethylene diamine is particularly advantageous since it actsas a wetting agent for viscose webs. Ethylene diamine is preferably usedin a concentration of from about .05 to .25 mole per each mole of maleylcompound in said methylol amide.

. The methylol amide binders of this invention can be used indispersions containing from about 1% to 60% by weight binder solids. Itis generally preferred, however, that the binder solids be in the rangeof about'5% 1 to 30% by weight in order to facilitate the application ofthe binder to the fibers by spraying, dipping, or by transfer rolls.

The binders of the present invention are characterized not only by goodadhesion to hydrophilic fibers like cot ton, regenerated celluloserayons and the like, but they are also characterized by excellentadhesion to hydrophobic types of fibers, such as the nylons, especiallypoly(hexamethylene adipamide), the vinyl resins such as copolymers ofvinyl chloride with vinyl acetate or with acrylonitrile, polymers of 70to acrylonitrile with other monomers such as vinyl chloride, vinylacetate, any of the vinyl pyridines. such as 2-vinyl pyridine ormixtures of such auxiliary comonomers, polyesters, such as poly(ethyleneterephthalate), and cellulose esters such as cellulose acetate,cellulose acetate propionate, cellulose acetate butyrate and so on.Because of the characteristic adhesion of the binder of the presentinvention to both hydrophilic and hydrophobic types of fibers, thefibrous products are characterized by excellent resistance to pillingand abrasion. The binder of the present invention is adapted to be driedand then cured to insoluble and infusible condition so that the bondscannot be disturbed even under severe conditions of heat. While thebinder may be preferentially applied, if desired, to portions of thefibrous product, such as one or both of the faces thereof, it ischaracteristic of the binder of the present invention that if suchpreferential treatment is not desired, substantially uniformdistribution may be obtained because of the reduced tendency of thebinder after initial distribution throughout the body of the fibrousproduct to migrate to the surfaces thereof during drying.

The binder of the present invention may also contain: dyes ofwater-dispersible type if coloration is desired; lubricants and/orsofteners of water-dispersible type. Emulsified polyethylene is thepreferred softener for use with the methylol amides of this invention.The emulsified polyethylene can comprise from about 1 to about 100 partson a dry solids basis (D.S.B.) for each 100 parts of methylol amide(D.S.B.). Best results have been obtained using from to 60 parts(D.S.B.) for each 100 parts methylolamide (D.S.B.).

The cured or insolubilized binders of this invention, wherein saidbinder has on an average at least 4 potentially reactive carboxy groupsper molecule (preferably at leastS) are unaffected by water or organicsolvents, such as perchloroethylene and carbon tetrachloride, even atmolding temperatures, whereby the bonded fibrous products are adapted tobe used as molding preforms or molding inserts for the production ofmolded articles from various thermosetting resins as will be pointed outin more detail hereinafter. After cure the binders are also free of coldflow and are resistant to flow at elevated temperatures, wherebyshifting of the fibers or filaments in the bonded products is almostcompletely prevented even at elevated temperatures during subsequentmolding when such products are used as reinforcing inserts or preforms.

In accordance with the present invention, the fibers of the non-wovenWeb may comprise wool or may consist entirely of non-proteinaceousfibers which are incapable of felting. The fibers are present in theform of a so-called non-woven mat in which they are haphazardlydistributed, or the mat may be formed by carding when the fibers are ofsuch a character, by virtue of length and flexibility, as to be amenableto the carding operation. Natural fibers like wool, linen, silk, jute,sisal, ramie, hemp, and cotton may be used, as well as many artificialfibers or filaments including rayon, those of cellulose esters such ascellulose acetate, vinyl resin fibers such as those of polyvinylchloride, copolymers of vinyl chloride with vinyl acetate, vinylidenechloride or acrylonitrile containing a major proportion of vinylchloride in the poly mer molecule, polyacrylonitrile and copolymers ofacrylonitrile with vinyl chloride, vinyl acetate, methacrylonitrile,vinyl pyridine, or with mixtures of such comonomers and containing amajor portion from 75 to 95% of acrylonitrile in the copolymer molecule;also condensa tion polymers such as polyamides of nylon type, polyesterssuch as ethylene glycol te'rephthalate polymers and the like. The thinweb or fleece obtained from a single card may be treated in accordancewith the present invention, but generally it is necessary and desirableto superpose a plurality of such webs to build up the mat to suflicientthickness for the end use intended particularly in the making of heatinsulation. In building up such a mat, alternate layers of carded websmay be disposed with their fiber orientation directions disposed at 60or 90 angles with respect to intervening layers.

Mats may also be formed by the deposition of fibers, either natural orartificial, from an air stream. Thus, continuous filaments may be fed toa cutter or breaker which discharges the fibers into the discharge sideof a blower. Suitable conduits are provided to guide the fibers to acollecting screen or air-pervious structure for collecting the fibers inthe form desired. The screen may be in the form of an endless travelingbelt passing through the lower portion of a tower into the upper portionof which the blown fibers are introduced by the conduit work. A suctionbox may be disposed beneath the upper course of the traveling screen toassist in the disposition of the fibers thereon. instead of having atraveling flat screen, a stationary formed screen may be used. Forexample, it may take the form of a hat-shaped cone such as that used inthe felt hat-making industry. Alternatively, it may have any other formsuitable to produce the desired shape of the fibrous product, such as arectangular tray. Again, suction may be applied beneath the screen toassist deposition of the fibers thereon.

The fibers and filaments may be formed by direct spray ing from asolution or molten mass thereof. This is a conventional procedure forthe formation of glass fibers or mineral wool fibers as well as those ofnylon or of thermoplastic materials, such as vinyl resins of the typementioned hereinabove, adapted to be dissolved in a suitable solvent,such as acetone or dimethyl formamide, or to be melted. The solution ormelt is, of course, directed to suitable nozzles or jet-forming orificesand a high pressure fluid stream, such as of cold or hot air or of inertgases such as nitrogen or even of steam, is directed against the streamor streams of filament-forming material to disrupt them and coagulatethem as fibers in the vicinity of the orifices. Electrostatic spinningmethods may also be employed for this purpose. As in the case of the useof blowers, the disrupted and dispersed fibers may be directed to thetop of a settling tower and be allowed to settle with the aid of suctiondevices upon a suitable travel ing or stationary screen at the bottom ofthe tower. This procedure is adaptable to the production of fibers ofsiliceous materials such as glass or mineral wool as well as tothermoplastic resin fibers mentioned above.

Another procedure may involve the extrusion of continuous filamentseither from solutions of the filamentforming material or from moltenmasses thereof, and the cutting or breaking of the filaments to fibersof a predetermined length which may be fed to a hopper at the top of asettling tower into which they may be discharged by conventional feedingdevices, and at the bottom of which a traveling or stationary screen maybe located for collection of the fibers.

The fibers and filaments that may be uesd in the present invention maybe natural or artificial as stated above. The selection of theparticular material of which the fiber is made frequently depends uponthe intended use of the product. For example, siliceous fibers areextremely valuable in the production of molded articles because of theexceptional strength obtained by their use. However, when the bondedfibrous products are used for filtration purposes, fibers of certainresins may be preferred to provide resistance to attack by acids oralkalies that may be present in the liquids to be filtered. Thus,polymers containing a high percentage of acrylonitrile or of vinylchloride or even of such highly halogenated resins aspolytetrafluoroethylene or poly(chlorotrifluoroethylene) may be moreuseful in such cases. For certain purposes, it may be desirable to formthe fibrous products from a mixture of fibers of different types. Anexample is the use of a mixture of thermoplastic fibers of potentiallyadhesive character with other fibers which lack such potentiallyadhesive character. A fibrous product comprising such a mixture may beheated to the appropriate temperature to render the potentially adhesivefibers tacky to effect binding of the fibers in the product by thisprocedure as well as by the binders of the present invention.

The binder dispersion may be applied to the dry fibers after theformation or deposition of the web or mat so as to penetrate partiallyinto or completely through the interior of the fibrous products.Alternatively, the binder dispersion may be applied to the fibers asthey fall through a settling chamber to their point of deposition. Thisresult is advantageously obtained by spraying the binder dispersion intothe settling chamber at some intermediate point between the top and thebottom thereof. By s spraying the fibers as they descend to the point ofcollec tion, it is possible to elfect a thorough distribution of thebinder among the fibers before they are collected into the product. Inthe production of certain fibrous products wherein a hot molten mass ofa polymer, such as nylon or a fused siliceous mass or glass, isdisrupted by jets of heated air or steam, the binder dispersion may besprayed directly on the fibers while still hot and very shortly beforetheir deposition so that quickly after deposition the binder is set andbonds the fibers in proper relationship. Preferably, however,application of the binder dispersion to the fibrous product is made atroom temperature to facilitate cleaning of the apparatus associated withthe application of the binder dispersion. The binder dispersion may beapplied to one or both surfaces of the fibrous product or it may bedistributed through the interior as well. If desired, the binder of thisinvention can be applied as a size to the fibers, prior to the formationof the web.

The binder of the present invention may be used in conjunction withother binders. For example, the methylol amides of this invention can beused in conjunction'with homopolymers and copolymers of vinyl acetate,vinyl chloride, vinylidene chloride, acrylonitrile, styrene, acrylic andmethacrylic acid esters; e.g. the methyl, ethyl, propyl or butyl estersthereof, and so on. The methylol amide of this invention may comprisefrom 1 to 100% of the binder solids. Compositions comprising from about5% to 50% methylol amide and from about 95% to 50% polyvinylacetate,give rise to non-wovens having markedly better water-resistance andsolvent resistance than non-Wovens based solely on polyvinyl acetate.Likewise, the adhesion of acryiate binders is improved by small amountsof methylol amide.

The fibrous product of non-woven character may contain from about /2 toabout 200% by weight binder on the weight of the fibers depending on thepurpose for which the product is to be used. When the binder is to servemainly to bond the fibers together to form a coherent unitary structurein which the maximum porosity is retained together with a minimum changeof natural fiber hand, there may be employed from /2 to 1% by weight ofbinder solids on the fiber, the lower proportion, of course, giving themaximum porosity possible and providing a minimum change in the naturalfiber hand although even with the larger proportion in this range, theporosity is mainly retained and the fiber hand is still evident. It ischaracteristic of the binder applied in the proportions just stated thatthere is relatively little or no window paning, that is, the intersticesbetween fibers are left open leaving a highly porous bulky product.Window paning does not result since the methylol amides employed in thisinvention are actually dissolved in the aqueous medium, unlike prioremulsion binders. Of course, the density of the product can be effectedor modified by the application of pressure prior to or, in many cases,even after the curing of the product.

Fibrous products of non-Woven character using from 2 to 30% by weight ofthe binder of the present invention on the weight of the fiber aregenerally quite useful in garments, for example as interlining fabricsfor coats, dresses, and so on, or to provide outer wearing apparelfabrics, such as blouses, skirts, shirts, etc. The garments made ofthese fabrics need little or no ironing, or pressing, to restore theirappearance, shape and hand after hand-Washing, machine-laundering anddrying operations. Besides the apparel uses mentioned above, fibrousproducts of the invention in which /2 to 20% by Weight of binder on theweight of fiber is employed, find many light industrial uses as wipingcloths, lining materials for packaging as filters, and packings andgaskets for industriallaminating layers, either as interlayers orbacking sheets in conjunction with plastic fihns and sheets as ofpolyethylene, nylon, and so on, or in conjunction with textile fabricsof woven, braided, knitted, knotted, or felted character.

To render the binder infusible, curing temperatures in the range ofabout C. to 350 C. may be used. Generally, temperatures in the range ofto 200 C. f about 1 to 10 minutes are suflicient.

Catalysts, such as melamine dissolved in formalin, hexamethylene'tetramine, ammonium p-toluene sulfonate, zinc ammonium acetate, zincfluoroborate, zirconium ammonium acetate, ammonium vanadate, ammoniummolybdate, etc. can be used to speed up the cure. The catalyst can beused in a concentration up to 5% by weight based on the dry weight ofthe methylol amide in order to speed up the cure or permit the use oflower cure temperatures. In the absence of a catalyst the rate of cureis impractically slow at temperatures much below C.

The following examples are merely illustrative and should not beconstrued as limiting the scope of the invention.

Example I A 10" by 20" piece of 100 percent viscose carded web Weighingabout 0.3 ounce per square yard was sandwiched between supportingglass-fiber screening and then impregnated by dipping the sandwich intoa 15 percent active material solution of a a methanol amide (preparedfrom soybean oil, maleic anhydride, ammonia and form-aldehyde, asdescribed before) having on an average 6 potentially reactive carboxylgroups per molecule. The impregnated sandwich was then passed throughthe steel and hard rubber rolls of a two-roll Birch padder at 25 p.s.i.roll pressure. The supporting glass fiber screening was removed and theimpregnated web was placed on paper and dried at 40 C. for one hour.After drying, the web was cured at C. for four minutes. The Web was thencalendered twice on the padder at 65 p.s.i. with the steel rollsimmersed in hot water 140 F. and dried for one hour at 40 C. Theresulting non-woven fabric, which was about 60 parts by weight fiber and40 parts by weight binder, had a texture similar to a non-woven webprepared with polyvinyl acetate. However, the web had markedly betterorganic-solvent resistance, detergent resistance and water resistancethan a non-woven web prepared with polyvinyl acetate. Further, thenon-woven fabric did not have the objectionable noisy handcharacteristic of nonwoven fabrics prepared with polyvinyl acetatebinders.

The methylol amide used in this example was prepared in the followingmanner.

Eight hundred and eighty-four grams of bleached soybean oil (1 mole) washeated to 230 C. in a threenecked flask equipped with a stirrer, refluxcondenser and addition port. After 294 grams (3 moles) of liquid maleicanhydride was added through the addition port over -a period of one andone-half hours, the composition was heated to 250 C. and held there for15 minutes. The maleated oil, after cooling to about 50 C. was added to700 grams of aqueous ammonium hydroxide (6 moles ammonia) and then thereactants were maintained at between 25-50 C., thereby dissolving themaleated oil. It was determined, by distilling 01f ammonia from aslightly basic sample of the solution, that about 42.5

of the potentially reactive carboxy groups (85% of the startinganhydr-ide groups) had been converted to the amide form. Five hundredand fifteen grams of formalin (6.3 moles formaldehyde) were :addedrapidly to the solution and the pH of the aqueous system dropped toabout to 5.5 precipitating the methylol amide as a water-insolublehydrate. The water-insoluble hydrate was redissolved by slowly adding143 grams of aqueous ammonium hydroxide (2.1 moles ammonia) whilemaintaining the exothermic reaction at about C. The solution had a pH ofabout 7. Then 21.2 grams ethylene diamine (0.35 mole) and 52.0 gramsaqueous ammonium hydroxide (0.77 mole ammonia) were added to adjust thepH of the aqueous solution of methylol amide to a pH of 7.58.5. Thefinal product was approximately active material.

Example II (A) Example I was repeated with essentially the same resultsexcept that the impregnated web was dried at 110 C. for 5 minutes andcured at 150 C. for 2 minutes instead of being dried at 40 C. for 1 hourand cured at 150 C. for 4minutes.

(B) When Example I was repeated using a roll pressure of 5 p.s.i. on theBirch padder the resulting nonwoven was approximately 25 parts by weightfiber and parts by weight binder.

(C) When Example I was repeated using a roll pressure of 60 p.s.i. onthe Birch padder the resulting nonwoven was approximately parts byweight fiber and 10 parts by weight binder.

Example III A non-woven disposable dust cloth was prepared by the methodof Example I using a methylol amide having on an average 3 potentiallyreactive carboxyl groups per molecule. The methylol amide was preparedby the method of Example I by reacting, in this order, 884 grams ofbleached soybean oil (1 mole), 150 grams maleic anhydride (1.53 moles),258.5 grams water, 177.8 grams aqueous ammonium hydroxide (2.6 molesammonia), 452.9 grams formalin (5.6 moles formaldehyde), 204 gramsaqueous ammonium hydroxide (3 moles ammonia), 18.6 grams ethylenediamine (0.3 mole) and 45.5 grams aqueous ammonium hydroxide (0.7 moleammonia).

The disposable wiping cloth was composed of about 55 parts by weightfiber and 45 parts by weight binder. It had a soft oily hand and wasresistant to water and carbon tetrachloride.

I 2 Example IV Example III was repeated except that no ethylene diaminewas used in the preparation of the methylol amide. The disposable wipingcloth, which was composed of about 88 parts by weight fiber and 12 partsbinder, had less strength and solvent resistance. This exampleillustrates that the incorporation of ethylene diamine in the methylolamide results in better wetting of viscose web.

Example V Example I was repeated except that one-third of the methylolamide in the impregnating bath was replaced by 5 parts, dry solidsbasis, emulsified polyethylene. The nonwoven fabric had essentially thesame properties as the non-woven fabric prepared in Example I exceptthat the non-woven fabric of this example had a soft hand. Thisnon-woven fabric had all the properties of a non-woven fabric preparedwith the most expensive acrylate polymers.

Essentially the same results were obtained when the viscose webs wasreplaced by a percent Acrilan (polymerized acrylonitrile) Web, an 80%acetate-20% nylon blend and a 100% polyethylene terephthalate Web.

Example Vl Example I was repeated using an impregnating bath containing1.8% (active ingredients) methylol amide of Example I and 13.2% (drysolids basis) polyvinyl acetate emulsion. The non-woven fabric hadmarkedly better organic-solvent resistance (carbon tetrachloride),detergent resistance and water resistance than a non-woven fabricprepared with 15% (dry solids basis) polyvinyl acetate. Further, thenon-woven fabric was not noisy.

Example VII This example illustrates the compatibility of the methylolamide of Example I with a number of commercially available polymers,which compositions can be used to prepare suitable non-woven fabrics.The methylol amide of Example I (60% active material) and the variouscommercially available polymers were compounded on an as is basis and at20% total solids. The compatibility of the various systems is set forthbelow in Table IX. In the table, the top line, or A line, represents theas is composition; the bottom line, or B line, represents thecomposition at 20% total solids. 1 stands for incompatible; PC standsfor partly compatible; C stands for compatible; T.S. for total solidsand stands for high viscosity.

TABLE IX Ratio of Methylol Amide of Example I to Polymer Test Polymer1:4 1:1 4:1

Imme- 8 hours on 24 hours Imme- 8 hours on 24 hours Irmne- 8 hours on 24hours diate standing at F. diate standing at 125 F. diate standing at125 F.

Darex 81L (55.8% T.S) A I I I 0 PC PC 0 PC PC Polyvinyl Acetate.-. B C IPC 0 PC I C I I Elvacet 81-900 (55% T A C I I 0 PC PO 0 PC PC PolyvinylAcetate B C C C C I I C I I Polyco-694 (55% T.S.). A O I I C I I C I IPolyvinyl Acetate B C 0 PC C 0 PC 0 PC 0 Pliolite Latex (47.5% T.S.) A 0PC I C 0 0 C C PC 40 Styrene-60 Butadieue B C C C C C C C PC C PlioliteLatex (48.9% T S A C C I C PC PC C PC PC 33 Styrene-67 Butadiene... B CC C C C C C PC PC Pliolite-440 (45% T.S.) A C I I C C C C PC PC 35Styrene-65 Butadiene B C I I C C C C PC PC Dylex K-40 (48.9% T.S.) A CPC PC C C C C C C 60 Styrene-40 Butadiene B C C C C C C C C C CelaneseVX-567 (50% T.S.) A C 0 PC C PC I 0 PC PC Acrylate B C C C C C C C C CGoodrich 450X3 (54.9% T.S. A C 0 PO C PC I 0 PC PC PolyvinylChloride-Aerylic. B C C C C I I O I I Hycar-157l (41% 1.S.) A O (3* C CO I C C" (3* Acrylonitrile Butadiene. B C C C C C C O C C Hymn-2671(50.3% T.S.) A C 0* PC 0 0' PC 0 C 0* Aery te B C C C C C C C C CRhoplex 1111-8 (46% T.S A C C C C 0 PC 0 PC PO Aerylate B C C C C C C CC C Rhoplex HA-IG (46% T A C C O 0 PC PC 0 0 PC B G C C C C C C G OAcrylate TABLE IXContinued Ratio of Methylol Amide of Example I toPolymer Test Polymer 1:4 1:1 4:1

Imme- 8 hours on 24 hours Lmme- 8 hours on 24 hours Imme- 8 hours on 24hours diate standing at 125 F. diate standing at 125 F. diate standingat 125 F.

Rho lex AO-55 55 T.S. A PC* PC* 0 0* PC* C G C Acry late in? -2 B C C CC C O C I I ShaWinigau 0566 (50% 'I.S A C C C 0 PC PC 0 PC PC PolyvinylButyi'al. B C C O C PC I C PC oly- M s A C O C C 0 PC 0 PC PCPolyethylene B C C O C C C C C 0 Since many embodiments of thisinvention may be made and since many changes may be made in theembodiments described, the foregoing is to be interpreted asillustrative only and our invention is defined by the claims appendedhereafter.

We claim:

1. A non-woven fibrous product in which the fibers are distributed inrandom array and bonded together by a binder wherein said binder whichis cured to an insoluble condition in an uncured state comprises awater-dispersible methylol amide of an adduct formed by reaction betweena maleyl compound an an ethylenically unsaturated aliphatic compoundhaving a chain of from to 24 carbon atoms containing on an average atleast 2 potentially reactive carboxy groups.

2. The article of claim 1, wherein said ethylenically unsaturatedcompound comprises an ethylenically unsaturated fatty acid ester of apolyhydric alcohol.

3. The article of claim 2, wherein said maleyl compound comprises acompound selected from the group consisting of maleic anhydride andmaleic acid.

4. The article of claim 3, wherein said ethylenically unsaturated fattyacid ester of a polyhydric alcohol comprises an ethylenicallyunsaturated glyceride oil.

5. The article of claim 4, wherein said methylol amide contains on anaverage at least 4 potentially reactive carboxy groups.

6. The article of claim 5, wherein said binder also comprises anaddition polymer of at least one monomer selected from the groupconsisting of ethylene, vinyl acetate, an alkyl ester of acrylic acidand an alkyl ester of methacrylic acid.

7. A non-woven fibrous product in which the fibers are distributed inrandom array and bonded together by a binder wherein said binder whichis cured to an insoluble condition in an uncured state comprises aWater-soluble product prepared by the steps of 1) reacting a compoundcontaining a basic nitrogen atom with an adduct formed by reactionbetween a maleyl compound and an ester of an ethylenically unsaturatedfatty acid of from 10 to 24 carbon atoms with a polyhydric alcoholhaving from 2 to 6 hydroxyl groups, wherein said adduct contains on anaverage at least 4 potentially reactive carboxy groups per molecule, and(2) reacting an aqueous solution of the reaction product of step (1)with formaldehyde.

8. The article of claim 7, wherein said maleyl compound comprises acompound selected from the group consisting of maleic anhydride andmaleic acid, and said compound containing a basic nitrogen atomcomprises ammonia.

9. The article of claim 8 wherein at least one-half mole of ammonia isadded in step (1) per each potentially reactive carboxy group in saidadduct and at least about 0.7 mole of formaldehyde is added in step (2)per each equivalent of nitrogen containing compound bearing an NH group.

10. The article of claim 8, wherein said compound containing a basicnitrogen atom also comprises ethylene diamine.

11. The article of claim 9, wherein said ester of a polyhydric alcoholand an ethylenically unsaturated fatty acid ester comprises anethylenically unsaturated glyceride oil.

12. The article of claim 8, wherein said binder also comprises a polymerof vinyl acetate.

13. The article of claim 8, wherein said binder also comprises a polymerof ethylene.

14. A process of making a non-woven fabric which comprises associating amass of fibers in random array within a web, bringing into contact withsaid fibers an aqueous dispersion containing 1 to 60% by weight of abinder, wherein said binder comprises a water-dispersible methylol amideof an aduct formed by reaction between a maleyl compound and anethylenically unsaturated aliphatic compound having a chain of from 10to 24 carbon atoms containing on an average at least 2 potentiallyreactive carboxy groups, drying the fibrous mat containing said binderand curing the binder to an insoluble infusible condition.

15. The process of claim 14, wherein said ethylenically unsaturatedcompound comprises an ethylenically unsaturated fatty acid ester of apolyhydric alcohol.

16. The process of claim 15, wherein said maleyl compound comprises acompound selected from the group consisting of maleic anhydride andmaleic acid.

17. The process of claim 16, wherein said ethylenically unsaturatedfatty acid ester of a polyhydric alcohol comprises an ethylenicallyunsaturated glyceride oil.

18. The process of claim 17, wherein said methylol amide contains on anaverage at least 4 potentially reactive carboxy groups.

References Cited UNITED STATES PATENTS 2,188,885 1/1940 Clocker 260404 X2,355,265 '8/1944 Bock et a1 117-161 X 2,637,663 5/1953 Thurston 117-167X 2,833,283 5/1958 Spahr et a1 117-140 X 2,915,418 12/1959 Wolfrom117140 WILLIAM D. MARTIN, Primary Examiner. T. G. DAVIS, AssistantExaminer.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,345,207 October 3, 1967 George W. Cogswell et al.

It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

Column 1, line 60, for "within" read without column 2, line 19, for"longe" read long line 62, for "25" read 24 column 3, line 5, for "acidcitraconic anhydride, itaconic acid itaconic" read acid, citraconicanhydride, itaconic acid, itaconic column 4, line 37, for "10% to 3%"read 10% to 33% column 5, line 63, for "ring" read ring) column 7, line61, for "portion" read proportion column 8, line 10, for "disposition"read deposition line 11, for "instead" read Instead column 10, line 40,for "of a a methanol" read of a methylol column 12, line 20, for "webs"read web column 13, line 27, for "an", first occurrence, read and column14, line 37, for "aduct" read adduct Signed and sealed this 22nd day ofApril 1969.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. EDWARD J. BRENNER Attesting Officer Commissionerof Patents

1. A NON-WOVEN FABROUS PRODUCT IN WHICH THE FIBERS ARE DISTRIBUTED INRANDOM ARRAY AND BONDED TOGETHER BY A BINDER WHEREIN SAID BINDER WHICHIS CURED TO AN INSOLUBLE CONDITION IN AN UNCURED STATE COMPRISES AWATER-DISPERSIBLE METHYLOL AMIDE OF AN ADDUCT FORMED BY REACTION BETWEENA MALEYL COMPOUND AN AN ETHYLENICALLY UNSATU RATED ALIPHATIC COMPOUNDHAVING A CHAIN OF FROM 10 TO 24 CARBON ATOMS CONTAINING ON AN AVERAGE ATLEAST 2 POTENTIALLY REACTIVE CARBOXY GROUPS.